T4 DNA Polymerase catalyzes the synthesis of DNA in the 5'→3' direction and requires the presence of template and primer. This enzyme has a 3'→5' exonuclease activity which is much more active than that found in DNA Polymerase I (E. coli). Unlike E. coli DNA Polymerase I, T4 DNA Polymerase does not have a 5'→3' exonuclease function. It is applicable to 3? overhang removal to form blunt ends, 5? overhang fill-in to form blunt ends, single strand deletion subcloning, second strand synthesis in site-directed mutagenesis and probe labeling using replacement synthesis. Theoretical protein molecular weight is 104000 daltons. Error Rate: ~ 1x10-6 bases